Bluetooth Low Energy (BLE) is a wireless personal area network technology designed and marketed by the Bluetooth Special Interest Group aimed at novel applications, in particular in the fields of healthcare, fitness, security and home entertainment. Compared to ‘classic’ or ‘conventional’ Bluetooth, BLE is intended to provide considerably reduced power consumption and cost while maintaining a similar communication range.
With classical BLE systems, at least a pair of BLE devices, one of which is denoted as a peripheral and the other one of which is denoted as a hub, are capable of establishing a communication link. Typically, the peripheral device advertises or broadcasts while the hub scans. Once the hub identifies a suitable peripheral device it requests a connection, pairs with the peripheral device and takes control over the peripheral device. At that time, the peripheral device stops advertising and communication becomes ‘closed’ so that communication is solely established between the hub and the peripheral device. For implementation of such a standard method, a complete BLE stack of hardware must be implemented for both BLE devices. In addition, once the communication between the pair of BLE devices has been established the communication takes place point-to-point. It is only visible to the hub and to the connected peripheral device.
Bluetooth Low Energy communication may also be established by a different mode, namely by non-connectable undirected advertising, in short ‘advertising mode’. There, the peripheral device only and exclusively advertises and is unwilling to and/or unable to pair or connect with the hub device. A drawback of this communication protocol is that there is no way for the peripheral device to get knowledge whether a broadcast packet or message has been correctly received by a hub device. Moreover, the peripheral device does not get any information about which of the multiplicity of available hub devices actually received or processed the previously broadcast packet or message.
Currently available BLE devices or so called BLE smart peripherals, when placed in advertise mode send packets of data, hence advertising packets, at regular intervals. Typically, the time interval between successive advertising packets is fixed. As a consequence the BLE device is in a constant or repeated need of sufficient electrical power. If the BLE device is implemented as a mobile device or if the BLE device is part of a mobile device, a power source, such as a battery will be depleted at a steady rate whether or not there is a reasonable expectation that a second BLE device, hence a viable hub is in the vicinity to receive and to process the advertising packets broadcast by the BLE device.